Punooraph co



H. A. HUMPHREYAND W. J. RUSDELL.

PUMP.

APPLICATION FILED APR. 6. I917.

Patented July 29, 1919.

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H A. IHUMPHREY AND W. LFUSDELL- PUMP.

APPLICATION FltED APR. 6, 1917-.

Patented July 29, 1919.

THE COLUMBIA PLANOGRAPH co., WASHINGTON, D. c.

H. A. HUMPHREY AND W. J. HUSDELL.

PUMP. 1,31 1,1 66. APPLICATION FILED APR. 5, I91]- 29 4 SHEETS-SHEET a.

Tm: COLUMBIA PLANOGRAPH co.. WASHINGTON D- c.

H. A. HUMPHREY AND W. J. RUSDELL. PUMP.

APPLICATION FILED APR. 6. I917. I 1,3 1 1,166. Patented July 29, 1919.

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SATES ra'r'r HERBERT ALFRED HUMPHREY, or Lounoiv, AND WILLIAM JOSEPH RUsnRLL, or WOLVERI-IAMPTON, ENGLAND, AssIGNoRs To I-IUMPI-IREY GAS PUMP COMPANY,

A CORPORATION OF NEW YORK.

Specification of Letters Patent.

PUMP.

Patented July 29, 1919.

Original application filed August 12, 1912, Serial No. 714,563. Divided and. this application filed April 6,

1917. Serial No. 160,306.

To all whom tit/may concern:

Be it known that we, HERBERT ALFRED HU PHREY and WILLIAM JOSEPH RUsnELL, both subjects of the King of Great Britain, residing, respectively, in London and VVolverhampton, England, have jointly invented certain new and useful Improvements in Pumps, of which the following is a specification.

Our invention relates to improvemnts in internal combustion pumps which have no flywheel, but have suitably heavy reciproeating masses. Our object is 'to provide improved means wherein the energy or a part thereof, which causes .a return stroke toward the combustion chamber or chainhers is limited by limiting the portion of such stroke which occurs under the influence of the delivery pressure.

In methods of raising or forcing liquid by means of the energy of expansion of an ignited combustible mixture it has been shown in several of our pending applications how it is frequently'desirableto employ an air vessel communicating with the play pipe (sometimes hitherto called the discharge pipe) and during movement of a column of liquid outwardly from a combustion chamber or chambers energy .is stored in an elastic medium contained in such. airwessel and utilized to produce an inward movement or movements of the said column. It has been. described. how by such means liquid orela-stic fluidcan be forced through non-return delivery valves under high pressure, and where liquidis to be raised or forced it has been desirable that the said non-return valves should open into i a second a1r vessel, stand pipe, or equlvalent device from which no liquid returns into the play pipe. Our present invention consists in permitting a return flow of a. definite and adjustable amount .into or toward the play "pipe. from the last mentioned air vessel or its equivalent with the object of furnishing apart or the whole of the energy required to produce'the inward stroke or strokes of the liquid column or other reciprocating'masses toward the combustion chamber or chambers. For, this purpose we may make use of the cyclical variations in level of liquid in the last mentioned air vessel or its equivalent to operate a float, piston, fioat-c0ntrolled valve or equivalent device situated in or communieating with the air vessel, and in such case the air vessel first mentioned in this specification and the non return valves may no longer benecessary, but either or both may be used in conjunction with the arrangement now proposed. We use a multiplicity of floats, pistons, or the like when large areas are required to deal with large volumes of liquid or elastic fluid. As our object may be attained by delaying the closing of the communication between the air vessel and the play pipe a suitable timing device, dashpot or the equivalent may be fitted to the liquid delivery valve instead of using a float or the like.

i This application is a division of our application Serial Number 714,563, filed Aug. 12, 1912 resulting in Patent No, 1,224,931 datedMay 8, 1917.

Referring to the drawings, which illus trate merely by way of example, suitable means for effecting our invention Figure 1 is a vertical section of apparatus showing a valve-controlling float of limited movemjentin the air chamber.

Fig. 2 is a vertical. section of the air chamber end of our device showing a valve controlling piston in the air chamber.

Fig. am a similar view of further modifications showing a float-valve.

Fig. 1 is a view similar to Fig. 2, showing the valve seat supported on a resilient cushion.

Fig. 5 is asimilar View on an enlarged scale of the air chamber end of Fig. 1, with modified arrangement between valve float.

Fig. 6 is a similar view showing a further modification comprising a conical valve.

Fig. 7 is a similar view showing further modifications, comprising a conical water tower into which liquid is delivered under pressure.

Fig. 7 is a sectional detail showing a valve fitted on the air vessel adapted toopen on its own weight and to be closed by lmpact of l1qu1d.

Fig. 7 is a similar view, showing a valveo controlled dip pipe fitted 1n the air vessel.

Fig. 8 is a vertical section, showing further modifications, comprising a piston valve combined wlth an air vessel, instead of with a water tower, as shown in Fig. 7

Fig. 9 is a similar viewshowing a suitable arrangement for the case where it is convenient to place the combustion chamber at a lower level than the liquid supply.

F igplO is a similar view showing arrangement suitable where motion of the liquid column on an outstroke is required before valve4 opens.

Fig. 10 is a sectional detail showing a dash-pot control for the piston in either direction of movement.

Fig.11 is a vertical section showing a conical float valve adapted to seat in conical extension of the play pipe.

Fig. 1.2 is a View similar to Fig. 10, show ing modifications in air vessel and piston.

Fig. 13 is a vertical section of further modifications where reciprocating masses which acquirethe necessary momentum, are constituted by a solid piston composed of two parts having different diameters.

Fig. 14 is a similar view of a further modification, showing a vertical play pipe with the combustion chamber at its upper end.

Fig. 15 is atvertical section of a further modification, showing a vertical play pipe and means for pumping an elastic fluid.

Fig. 16 is a vertical section of an arrangement suitable for raising water from a well showing that part of the pump which is in or close to the water to be raised.

Fig. 17 is an elevation on a reduced scale, showing the general position of the several parts.

Similar numerals refer to similar parts throughout the several views.

In Fig. l, 1 is the combustion chamber of an internal combustion pump, 2 the play pipe in which a column of liquid reciprocates, 3 are the inlet valves for liquid, 4 a delivery valve for liquid under pressure having a float 5 adapted to slide within limits on the stem of the valve, 6 is the liquid intake pipe, and 7 the liquid delivery pipe which discharges from the air vessel 8. If the pump is of the 2-cycle type, then when ignition of a. compressed combustible charge occurs in the top of chamber 1 liquid will be driven downward in chamber 1 and along the play pipe 2 lifting valve 4 off its seat so that liquid is discharged under pressure into the air vessel 8 causing the level of liquid therein to rise and carry with it the float 5. hen the column of liquid comes to rest in pipe 2 valve 4 is held off its seat by the float 5 and liquid can flow from air vessel 8 partly through the delivery pipe 7 and partly back into pipe 2 under the pres sure existing in the air vessel. In the meantime products of combustion may have been wholly or partly expelled and a fresh combustible charge introduced into chamber 1 and the liquid flowing from air vessel 8 into pipe 2 gives the return stroke which compresses a fresh combustible charge. The fall of level of the liquid in air vessel 8 permits float 5 and valve 4 to descend unt1l valve 4 cuts off communlcat1on between the air vessel 8 and the pipe 2 whereupon the momen- 1 is compressed and the liquid in pipe 2 again atrest valves 3 shut and everything is ready for the commencement of anew cycle.

If the apparatus works on a 4-stroke cycle then the first outstroke is caused by the energy of combustion in chamber 1. The first instroke is caused by liquid which returns under the pressure in air vessel 8 into pipe 2 before valve 4 closes. The second outstrokeis produced by the expansion of an elastic cushion which was retained in the combustion chamber and compressed on the first instroke, and the second instroke is caused by liquid which flows from the air vessel 8 into pipe 2. During the first instroke exhaust gases are expelled from chamber 1 and fresh liquid is taken in through valves 3 and during the second outstroke a fresh combustible charge is taken into chamber 1 which is compressed on the second return stroke in the manner described in previous specifications. Under some conditions liquid may be delivered past valve-4 on the second outstroke andfresh liquid taken in on the second instroke. It will be evident that the cyclical rise and fall of the liquid level in air vessel 8 will depend partly upon the rate at which liquid is delivered through pipe 7, and this may be modified by making the inertia of the liquid in pipe 7 greater or less.

As the inertia. is increased the velocity of the liquid through pipe 7 will be more constant. r

Fig. 2 showsa modification in which valve 4 has a-stem aboveit whereon slides a piston 9, working in the cylinder 8 which constitutes an air vessel. past valve 4, piston 9 is raised until it engages with the collar on the valve spindle;

it then carries the valve with it a distance depending upon the amount of air in air vessel 8, and the amount of water delivered past the valve. Theair in the air vessel will be compressed and 011 a return stroke the pressure of the expanding air acting on piston 9 will force liquid back past valve 4 into the pipe 2 to furnish the energy. for the return stroke. When valve 4 closes piston 9 may fall still lower because it can slide along the valve stem. The piston 9, therefore, serves a similar purpose to the float 5 but has the advantage that it separates the liquid delivered from the elastic fluid in vessel 8 and so partially prevents the absorption of the elastic fluid by the liquid. In order to vary the capacity of, or pressure in, vessel 8 As liquid is delivered.

an auxiliary air vessel 10 communicates with 8 and is fitted with two cocks 11 and 12 for elastic fluid and liquid respectively. Thus more or less elastic fluid can be introduced under any desired pressure and the total capacity for elastic fluid can be varied by altering the quantity of liquid in vessel 10. i

In Fig. 3, a spherical valve 13 which is made as a float takes the place ofthe combined valve 4 and float 5 of Fig. 1. Also, 13 is shown movable in a cylinder 14, the efiective capacity of which may be adjusted by moving the cylinder up or down to lengthen or shorten the portion in which 13 moves. The action is as follows :-On an outstroke float valve 13 is lifted from its seat 15 until it is high enough to permit the escape of liquid over the top edge of the cylinder 14. Guides 16 hold 13 in position so that when the liquid in pipe 2 comes to rest 13 is ready to fall with the liquid in cylinder 14 as the latter is forced downward by the pressure in vessel 8 which produces a return flow. The volume of liquid under pressure which moves toward pipe 2 is substantially that displaced by the descent of 13 from its upper position until it rests upon the seat 15 and closes communication with the pipe. 2. This volume being a definite amount and the average pressure in the vessel 8 being also definite the amount of energy expended in the manner described to produce a return stroke will be a known and definite quantity and independent of the cyclical change of level of the liquid in air. vessel 8 but outside cylinder 14, provided that the outside level does not rise beyond the upper edge of cylinder 14.

In 'Fig. 4, which is similar to Fig. 2, the valve 4 has a seat supported on a resilient cushion, in this case shown as anumber of rubber rings held in position by angle rings. Such an arrangement prevents shock when valve 4 shuts. i

Fig. 5 corresponds closely with Fig. 3 but instead of a spherical float valve 13 there is a combined float 5 and valve 4 which acts similarly to the corresponding parts of ,Fig. 1 except that the volume of liquid which returns on aninstroke is in this case a fixed quantity depending on the rise of valve 4 in cylinder 14 .(this. rise being in turn dependent-upon the level of the upper edge of the cylinder 14) and is independent of the cyclical variation of the liquid outside cylinder 14. By adjusting theposition of the float 5 on the stem of valve 4 the rise and fall of valve 4 and consequently the quantity of liquid which returns to pipe 2 may be made adj ustable.

It is sometimes desirable to have an elastic cushion between the pipe 2 and the valve which cuts 011 communication between this pipe and the air vessel 8, and one method of providing such a cushion is shown in Fig.

suit different circumstances.

6 where a conical valve 17 moves in a cylinder 14 above which it is guided by the projections 16 and thevalve stem 18. As liquid rises in pipe 2 and in the interior of the valve 17 it may shut the small valve 19 by impact and thus imprison a constant volume of air in the interior of the cone valve which serves as an elastic cushion. A spring loaded valve20 on the other end of the pipe 21 may serve to discharge air under pressure it there is more air in the cone than is required. It also acts as a non-return valve to prevent air being drawn back into the cone when the liquid in pipe 2 continues to move downward under its acquired momentum. It will be obvious that the air cushion must expand until the pressure at which valves 3 open is reached, and thatthen liquid will be taken in throu '11 these valves.

Fig. 7 shows a modi cation in which liquid is delivered under pressure into a conical water tower 22 and in whichthere is an additional air vessel 23 in communication with the play pipe 2 at. the delivery end. Further, the valve 4 is in this case a piston valve sliding in a horizontal cylinder 14 and attached by a rod 24 to a piston 25 sliding in a cylinder 26 which serves as a dash-pot or timing device. The operation in this case, assuming a 2-stroke cycle, is follows :On the outward'stroke from the combustion chamber the elastic cushion in 23 is compressed until the pressure attains that at which valve 4 is forced to the right far enough to cause it to open communication between pipe 2 and water tower 22. Then delivery of liquid occurs until the liquid column comes to rest. "On the return stroke liquid'flows from 22 toward pipe 2 carrying along with it the piston 4 until the motion of this piston is arrested by the dash-pot. The elastic cushion. in 23 then expands until the pressure is that at which valves 3 open and the last part of the return stroke causes the intake of liquid through valves 3. The air cushion in 23 permits the liquid in pipe 2 to acquire velocity before liquid is dis-- charged past valve 4 and thus permits a greater lift or a higher pressure to be obtained than is possible with the apparatus of Fig. 1. It is obvious that the valve 4 can be controlled in its movements by any known form of dash-pot or timing device and such movement may be adjustable so that the amount'of energy made available for producing the return stroke may be varied to V For. example, there may be air inlets fitted with cocks 27 and 28 communicating with cylinder 26 at different points so that the opening of one of these cocks and the closing of another may cause diflerent quantities of air to be trapped on the left hand side of piston 25 in order to vary the length of motion of the piston 4 before the compression of the air last mentioned brings the piston to rest in moving to the left.

In Fig. 7 the air vessel 23 is fitted with a valve 29 which opens under its own Weight and is closed by impact of liquid upon it.

uch an arrangement is useful where a high pressure of delivery is required but where there is no suction lift for the incoming liquid. It permits the air in 23, or some of it, to be exhausted on an outstroke and fresh air to be taken in on an instroke. In such case the liquid must flow into pipe 6 under gravity or ressure.

In Fig. b the vessel 23 is fitted with a downwardly projecting pipe 30 having a valve 29 at its lower end, its top end being open to the atmosphere. This arrangement permits a definite volume of air to be entrapped and compressed in 23 as the liquid rises on an outstroke, and the action of such an arrangement has been fully described in previous specifications.

111 Fig. 8 piston valve 4: is combined with an air vessel 8 instead of with a water tower 22 as shown in Fig. 7. The piston 25 attached to the valve 4 and moving in cylinder 26 in this case serves to inclose an air buffer in the lower part of 26 which will arrest the downward movement of valve 4. The upward movement of valve 4: and the first part of its downward movement are allowed to be free by the provision of an air inlet 31 in the wall of cylinder 26 so that air can be taken in through such aperture on the upstroke of piston 25 and discharged on the first part of the downstroke, but there always remains a cushion below piston 25 the compression of which arrests the movement of valve 4:. In this case there are provided air inlet valves 32 which open to admit air when piston 4 is arrested on the downstroke, and when sufficient air has thus been admitted to let the liquid in pipe 2 fall to the level a-a of the liquid in the liquid supply tank, valves 3 will open and fresh liquid will be taken in. If valves 32 are made to shut by impact of liquid this air, or the greater part of it, may be rejected again 011 the next outstroke before pistion 4. is caused to move upward but sufficient may remain to provide an elastic cushion below valve so as to avoid shock. It is frequently desirable that some air should be discharged past valve 4 into air vessel 8 to replenish any losses due to absorption of the air by the liquid.

Fig. 9 shows a suitable arrangement for the case where it is convenient to place the combustion chamber at a lower level than the liquid supply or the liquid intake valves, and where the energy for producing a return stroke may be largely due to liquid flowing under the action of gravity toward the combustion chamber. The piston valve 4: moving in the cylinder 14 allows a definite volume of liquid to return from the delivery tank 22 during an instroke before the valve is arrested by coming to its seat (and thereafter the further portion of the stroke may occur under the influence of liquid flowing toward the combustion chamber under gravity) and during the remainder of the stroke fresh liquid will be drawn up through pipe 6 to enter pipe 2 through valves 3.

WVhere motion of the liquid column on an outstroke is required before value l opens, but where only a small elastic cushion is re quired to be retained in the air vessel 23, the arrangement shown in Fig. 10 may be adopted. In this case there is a float or piston 33 fitted in the vessel 23 which contains openings 34 communicating with the atmosphere so that air may be taken into 23 as the float 33 descends and may-be discharged as the float ascends except that a small quantity of air is retained in the top of 23 to act as a cushion. A stop 35, preferably resilient, prevents-the float falling beyond a certain limit and thus enables liquid to be sucked through valves 3 during the latter part of an instroke. In this case the valve & is attached to a piston 25 moving in a cylinder 26 having the same function as cylinder 26 in Fig. 8 but so short that it is open at the top so that the piston can pass beyond the cylinder.

In Fig. 10 there is substituted for the float or piston 33 a piston 35 controlled both in its upward and downward motion by a piston 36 working in. a dash-pot 37 in such a manner that a cushion of air is retained and compressed in 37 both on the upstroke and on the downstroke. Such an arrange ment avoids the necessity for the stop 35 shown in Fig. 10.

In the modification shown in Fig. 11, there is a conical float valve 38 capable of being seated in a conical extension of pipe 2 into chamber 8. This float is forced upward on an outstroke and on an instroke, after allowing a certain quantity of liquid to return from air vessel 8 to pipe 2, it

closes communication in a similar manner to that of the combined valve 1 and float 5 of Fig. 1.

The arrangement shown in Fig. 12 is similar to that of Fig. 10 but instead of an air vessel 23 and a float or piston 33 there are an air vessel 39 and a piston 40 so arranged that energy may be stored during an out-stroke by compression of the elastic cushion contained in 39 when the piston 40 moves upward, such energy being given out again on a return stroke as the cushion in 39 expands and the piston 40 moves clownward. An approximately constant pressure may be kept in the vessel 39 by means of the pipe 41 which communicates with a liquid supply maintained at a suitable head in any suitable manner, not shown. It is not intended in this case that the piston 40 should pass beyond the limits of the cylindrical pipe in which it moves and its movements are consequently limited by a dashpot or other suitable device. With such an arrangement, if the pressure at which liquid is to be delivered is approximately the pressure of the elastic 'fluid in. vessel 39, instead of piston valve 4 there may be used ordinary non-return delivery valves and then the whole of the energy for a return stroke would be derived from the energy stored in 39.

' Fig. 13 shows an application of the invention to a case where reciprocating masses which acquire the necessary momentum are constituted by a solid piston composed of two parts 42 and 43having different diameter's. 1 is the combustion chamber shown diagrammatically and either of the 2-cycle or 4-cycle type. In the space 44 an elastic cushion can be retained when the piston 42 passes the port 45 and the compression of this cushion may partly serve to bring the reciprocating masses to rest and to furnish some of the energy for the return stroke. The parts 4 and 25 are numbered to correspond with previous figures in which the parts have similar functions but in this case the dash-pot or timing cylinder 26 wherein the piston 25 works, is fitted with a number of passages at the 'top and bottom, controllable by rotating valves 46 and 47, so arranged that one or more of these passages may be open at the top and at the bottom of the cylinder; in this way may be determined the point at which compression of the elastic cushion retained commences, the object being to control efficiently the movements of valve 4 to meet the requirements of various working conditions. As shown in the figure, cocks 46 and 47 communicate with the at mosphere at 48 and 49 but these two openings can be connected by a pipe so as to serve as a by-pass between the top and bottom of cylinder 26. Instead of the ordinary suction valves 3 which have been shown in previous figures, a piston valve 50 controlled by a dash-pot or timing device having a piston 51 may be used, and by attaching auxiliary cushion chambers such as 52 and 53, the communication between them and the ends of the cylinder in which piston 51 works being controlled by cocks, a useful means of controlling the valve 50 is provided. On a return stroke in which fresh liquid is to be taken in and when the pres sure to the left of piston valve 50 has fallen sufiiciently, the valve is urged to the left and when in its dotted position provides a passage for liquid to flow from the liquid supply tank into the apparatus under the partial vacuum therein existing or under the head or pressure of the supply. As the reciprocating masses come to rest the expansion of the elastic cushion compressed to the left of piston 51 will cause valve 50 to move to the right and cut off communication with the liquid supply.

Fig.14 shows an arrangement of pump in which the play pipe 2 is vertical and has the combustion chamber 1 at its upper end. 3 are the suction valves, 17 is a delivery valve moving in a cylinder 14 and guides 16 and closing upwardly on a resilient seat 15. On the suction side of valves 3 there is an air vessel 54 and there is an elastic cushion 55 close to the seating of valve 17 The intake of fresh liquid through valves 3 is caused in this as in other cases by the diminution of pressure due to the momentum of the liquid in pipe 2 moving toward the combustion chamber 1, after valve 17 has come to rest on its seat 15.

Fig. 15 illustrates one method of applying our invention to an elastic fluid pump, 1 is the combustion chamber, 42 a solid piston. which in this case reciprocates vertically, and 4 is the delivery piston valve working in a cylinder 14 and controlled by a dashpot or timing device 26 in which moves the piston 25 attached to valve 4 and serving to limit and control its motion. 8 is a delivery air vessel, inthis case for elastic fluid only, and 16 are guides for the valve 4 as it moves upward beyond the limit of the cylinder 14 to establish communication between the pipe 2 and the air vessel 8. Valves 56 are valves for the admission of fresh elastic fluid into cylinder 2 below and close to the lower limit to which valve 4 moves. Assuming a 2-stroke cycle in the combustion chamber 1, the action of the apparatus is as follows :On the upstroke of the piston 42 produced by the combustion; elastic fluid etween the top of piston 42 and piston valve 4 is compressed and valve 4 is moved upward until communication is established between vessel 8 and cylinder 2. When piston 42 comes to rest and begins to return, valve 4 moves downward with it until arrested by the compression of a cushion in the lower part of cylinder 26. Piston 42 will then continue to move alone and will take in a fresh supply of elastic fluid through valves 56 until the downward motion of the piston is arrested by the compression of a fresh combustible charge which has in the meantime been introduced into chamber 1, and thecycle is ready to be repeated. It may be that piston 42 will not rise to the upper edge of cylinder 14, and in this case when valve 4 and piston 42move downward again there will be some elastic fluid under pressure contained between them, which by expanding, will add to the energy producing the return stroke of the piston 42 toward the combustion chamber 1, and so cause a higher compression pressure and consequently a higher explosion pressure for the next upward stroke. The less the dis- 42 approximately constant.

tance piston 42 rises, the greater will be the quantity of air between this piston and valve 4: which is permitted to expand, and this {furnishes an automatic means tending to keep the upper limit of the stroke of piston There are shown a bypass and a valve 57 between the upper and lower parts of cylinder 26 by means of which the mot1on of piston 25 may be controlled.

Figs. 16 and 17 show the application of the invention to a pump suitable for raising water from a well, Fig. 16 being a sectional view of that part of the pump which is in or close to the water to be raised, and Fig. 17 showing the general arrangement of the plant. The combustion chamber 1 and the play pipe 2 are shown in a vertical position;

6 is the suction pipe and 7 the delivery pipe.

In Fig. 16 the inlet valve 3 is a ring supported by springs 58. Valve 4: and its cylinder 14: are numbered as previously, but in the present case the cylinder 14 is perforated by a number of holes so that the opening of in pipe 2 and rising around the bottom bend of this pipe forces up valve 4: thus delivering llquld under pressure 1nto air Vessel 8 'to be discharged through pipe 7 to the ele- 'vated tank 67. Energy is given for the return stroke due to the pressure in air vessel 8 and continues until valve 4 comes on its seat, at which time the liquid in pipe 2 has suflicientveloclty and momentum to take in by its continued movement fresh liquid past valve 3 and to cause compression of the combustible charge 111 chamber 1. The cycle can then be repeated by the ignition of the fresh charge. There is shown in Fig. 17 a hand pump 62 for delivering air through pipe 63 so that the desired pressure can be obtained in starting the pump. An air inlet pipe 64 is shown for supplying a controlled quantity of air to the suction air vessel and it may be arranged that some of this air passes liquid passing out of pipe 7, and such bubbles can be observed by a sight glass 65 which is provided at its top with a controllable outlet for air 66. I H

\Vhere the delivery pipe 7 islong, so that there is considerable inertia in the moving liquid, a useful modification is obtained by fitting the lower part of the air vessel 8 with suction valves for liquid and making the capacity for air of this vesselsmaller. It is then possible to cause liquid to enter the air vessel due to the continued'movement of the liquid in pipe 7 after valve 4 has closed and the pressure in the air vessel S-has been re duced.

It will be understood thata combustible charge has been given in the above description merely as an example of a suitable expansible medium, other ex ansible mediums are equally available in e 'ecting our invention as defined in the claims.

What we claim is c J 1. The combination of a play pipe, a mass for reciprocation therein having sufiicient "weight to acquire useful momentum, a power chamber for an expansible medium operating upon said mass to cause the power stroke, an

HERBERT ALFRED HUMPHREY. WILLIAM JOSEPH RUSDELL.

Witnesses to signature of Herbert Alfred Humphrey C. S. HoPKINs, TV. I. SKERLEW. WVitnesses to signature of l/Villiam Joseph Rusdell:

' SYDNEY G. DAVIES,

GWENDOLINE OWEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, 1). 0. 

